Making fixed railway track

ABSTRACT

A track system is made by setting a longitudinally extending row of concrete high-pressure injection piles in grown soil and then positioning atop the piles a succession of sleeper frames each including a pair of longitudinally extending rigid concrete beams held together transversely by a rigid steel structure. A longitudinally extending body of concrete is then cast between the beams around the steel frame. Finally longitudinally extending rails are fastened atop the beams.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is the US national phase of PCT applicationPCT/EP2003/010027, filed 10 Sep. 2003, published 14 Apr. 2004 as WO2004/031483, and claiming the priority of German patent application20215204.9 itself filed 1 Oct. 2002, whose entire disclosures areherewith incorporated by reference.

FIELD OF THE INVENTION

The present invention relates to a new type of fixed track system forrail traffic and to a method of manufacture thereof.

BACKGROUND OF THE INVENTION

Higher and higher rail traffic speeds have led to progressively moreproblems associated with the conventional railway design with aballasted track. In the high-speed railway networks of Germany and otherEuropean countries the conventional ballasted track as along-established, tried-and-tested system has reached its physicallimits and is no longer capable of meeting requirements such as minimalsusceptibility to faults and low maintenance costs combined with closedistance spacing and high track capacity and therefore has no long-termfuture.

As an alternative, in 1972 DB AG, scientific institutes and theconstruction industry developed the so-called fixed track constructionstyle, “Rheda,” which together with the construction style, “Züblin,”has been approved as the standard track for high-speed sections ofGerman Federal Railways since 1992. In fixed track systems, the trackformation layer and the gravel ballast of the conventional ballastedtrack are replaced by a hydraulically bound subbase with an asphalt orconcrete base course on top. The overall structure is regarded, andhence treated as a system—earthwork/concrete base course—that is to bestatically dimensioned. In contrast to ballasted track, it is very rigidand computationally determinable. The basic idea in developing the fixedtrack is to guarantee a uniform resilient bedding for the track, thisbeing achieved almost exclusively by resilient intermediate layers inthe region of the rail fastening or by resilient sleeper supportsystems. As a result, even in the speed range above 200 km/h the trackis supported uniformly and with lasting positional stability, whichmeans that e.g. larger cambers and hence higher cornering speeds becomepossible but also that maintenance outlay is negligible compared to theconventional trackbed.

Fixed track systems are subdivided mainly into two construction stylesor design principles: in the case of the first, concrete sleepers (alsoconcrete-block and steel tie-bars) or support blocks are embedded inconcrete and therefore connected to form a monolithic structure, thetrack grating having to be fitted and vibrated and/or bedded in withmillimeter accuracy. Later, this was changed to mounting and anchoringthe track gratings directly on an asphalt or concrete base plate, whichin turn has to be done continuously with millimeter accuracy. This hasthe advantage—not provided by a monolithic style of construction—ofenabling the exchange of the individual sleepers. Here, the individualsuppliers of fixed track systems vary in terms of conceptions and detailsolutions. There are currently seven selected systems being tested on anoperating trial section between Mannheim and Karlsruhe, includingsystems without sleepers, where the rail has been fastened directly ontosupport points of the concrete base course.

While the fixed track system offers many incontestable advantages, itdoes of course also have drawbacks, some of them system-related. Themain points of criticism are listed and explained below.

The Federal Audit Office has criticized the high cost of installingfixed track and pointed out that to break even financially with theconventional ballasted track a useful life of at least 60 years wouldhave to be achieved. The counter-argument to this is that it is possibleto eliminate measures such as screening, retamping and renovating oldballast sections that incur cost and disrupt rail traffic and thereforeto increase the degree of utilization of the railways. Despiteautomation and prefabrication, it is impossible to push the cost ofcreating the existing conventional fixed track systems down to thelevel, or below the level, of ballasted track, although there are alwaysattempts at optimization. The high capital outlay for creating fixedtrack systems is due to their more complex manufacture, which is alsoreflected in a much longer construction period. This arises from theneed for very high accuracy when laying track gratings and/or installingbase plates, the need for costly upgrading of the soil (except fortunnel construction), and the construction period interruptions entailedby hydraulically bound layers and troughs supported on and in oneanother. The fundamentally required preliminary work, referred to hereas costly upgrading of the soil, specifically means an exchange of thesoil to a depth of, at times, over 3.0 m and subsequent layer-by-layerincorporation and compaction of precisely mutually tuned functional baselayers in order to achieve the requisite properties, such as elasticity,stability, load distribution, frost protection, drainage etc. This alsomeans i.a. that the renovation and conversion of an existingdouble-tracked ballasted section to the fixed track system may becarried out normally only by totally closing both tracks owing to thedimensions and shape of the trench.

As the next specific problem, the increased emission of airborne noisecaused by the rigid structure and the absence of noise absorption iscited in many sources. Measurements and calculations have resulted in anairborne noise level increase of at most 3 dB(A), which has led to theuse of cost-intensive sound absorbers and other sound-absorbing measuresat the surface and in the edge region of the fixed track.

As a final and not unimportant drawback of all previous fixed tracksystems, the limited adaptability of the rail fastening and railposition owing to the monolithic structure is cited. Because the railfastening points are invariably fixed and the displaceability of therails is therefore limited to a minimal value, thereby making itrelatively impossible to modify or adapt the operating pattern, veryhigh demands are placed on the planning and surveying and designing ofthe route and the rail track. In contrast to the ballasted constructionstyle, therefore, both subsequent modifications of the rail position andminor alteration of the track route or enlargement of the camber as wellas point installation etc., if they are possible at all, are possibleonly with an extremely high outlay.

In summary, it should be stressed that with the currently availablefixed track systems high capital costs are incurred as a result of thefollowing parameters:

-   -   very high planning outlay also with regard to long-term        operational planning,    -   very high outlay for soil exchange according to requirements,    -   very high surveying outlay simultaneously with execution of        construction work,    -   very high construction outlay owing to the need for extreme        accuracy.

What is more, conversion of an existing, heavily used section is notpossible these days because of the need for total closure of both tracksand the long construction period.

OBJECT OF THE INVENTION

The object of the invention is, in a departure from the previous fixedtrack systems of diverse manufacturers and suppliers, to translate thecost-effectiveness and simplicity of design as well as the flexibilitywith regard to modifications of the track- and operating pattern of theballasted track design to the fixed track, while eliminating theprevious drawbacks.

SUMMARY OF THE INVENTION

According to the invention this object is achieved in the initiallydescribed fixed track system in that it comprises a frame-likestructure.

The subject of the invention is in particular a new type of fixed tracksystem for rail traffic comprising preassembled trackway rail carriersof statically delimited length, which run parallel to the track and aremounted on reinforced concrete composite piles nailed down undergroundby high-pressure injections and which in the frame-like assembled andaligned state enclose a trough, which is provided at an assembly sidewith a foil as a bottom termination and which once filled with castingcement forms a longitudinally and transversely reinforced, joint-free,continuous plate as an upper railway.

It is moreover proposed

that the sleeper frame 2 comprises two rail-parallel reinforced concreteprefabricated parts 3 of minimal manufacturing tolerance and of afinite, non-fixed length,

that preassembled trackway rail carriers of statically delimited lengthextending parallel to the track are provided,

that the trackway rail carriers are supported on reinforced concretecomposite piles, which are nailed down underground by high-pressureinjections,

that the reinforced concrete prefabricated parts 3 in the frame-likeassembled and aligned state form a trough provided at an assembly sidewith a foil as a bottom termination,

that the trough is filled with casting concrete and forms alongitudinally and transversely reinforced, joint-free, continuous plateas an upper railway,

that the reinforced concrete prefabricated parts 3 for the loads in thefinal state are manufactured pre-curved counter to the load camber,

that the parallel-running reinforced concrete prefabricated parts 3 arethe sleeper body,

that the sleeper bodies in the form of reinforced concrete prefabricatedparts 3 are held apart in the assembled state by steel structures 4, 10,

that the sleeper bodies in the form of reinforced concrete prefabricatedparts 3 are secured in position in the installed state by steelstructures 4, 10,

that the final fixing of the longitudinal sleeper frame 2 is achieved byfilling the space between sleepers to a defined height with castingconcrete 7 of an adequate ultimate strength,

that for packing a high-early-strength casting concrete 7 of an adequateultimate strength is used,

that the casting concrete 7 is provided with an adequately dimensionedreinforcing steel insert 9,

that for transmission of the dynamic loads an, in static terms,infinitely long plate is produced by means of the longitudinal fillingwith casting concrete 7 of adequate strength and an adequatelydimensioned reinforcing steel insert 9,

that the construction as a plate of infinite length dispenses with acostly soil exchange in the case of problematical subsoils,

that owing to the vertical clearance between the bottom edge of the railbody 14 and the top edge of the casting concrete 7 between the sleeperbodies 3 there is adequate room for the subsequent installation of pointsystems,

that fastening profiles 16 incorporated in the factory into theprefabricated part of the sleeper body 3 enable easy fastening ofadditional parts such as e.g. noise protection systems in the wheelregion or additional systems such as points,

that all of the fastening points 15 are accessible at all times andtherefore easy to maintain,

that the surface of the space filled with casting concrete 7 isconstructed with an adequate slope to allow surface water to drain away,

that as a possible upper layer a noise-absorbing concrete layer isapplied onto the casting concrete body 7,

that the casting concrete body 7 is sealed off in a downward directionfrom the frost protection layer 1 by means of a PE foil 5 of adequatestrength,

that the PE foil 5 acting as a seal against rising damp is connectedimperviously to the sleeper bodies 3,

that water is removed from the surface of the casting concrete body 7situated between the reinforced concrete sleeper bodies 3 by means of adrainage system 8, which is integrated in the factory into theprefabricated part,

that the longitudinal sleeper frame 2 as vertical and horizontal fixingis anchored on reinforced concrete piles 11, 12, which are nailed downunderground by high-pressure injections, and steel supports 13,

that the longitudinal sleeper frame 2 as vertical and horizontal fixingis anchored on steel-reinforced piles 11, 12, which are nailed downunderground by high-pressure injections, and steel supports 13,

that the anchoring piles 11, 12, 13 in terms of their anchoringdirection are orientated to the principal loading directions,

that by virtue of the anchoring on piles 11, 12 and steel supports 13the adjustment of the sleeper body 3 as a track carrier may be carriedout in the air without difficulty,

that the adjustment of the sleeper body 3 need be effected only at thesupport points at greater intervals along the foundation piles 11, 12,13,

that by means of this method even difficult subsoils are bridgeablewithout a greater outlay,

that the rail 14 is mounted by means of the conventional standardconnecting means 15 on the new type of sleeper bodies 3 and anchored ina laterally displaceable manner in the fastening sections or profiles16, which are embedded in concrete transversely of the rail position inthe rail fastening spacing,

that the rail body 14 rests on a ribbed plate,

that the rail inclination is freely adjustable by means of the ribbedplate,

that the rail body 14 is laterally displaceable on the ribbed plate 15in the released state of the fastening means 15,

that the rail 14 is acoustically isolated from the substructure 1 bymeans of a sound deadening mat 6 laid therebetween,

that an adaptation to different gauges entails merely the appropriatevariation of the steel structures 4, 10 but no variation of thereinforced concrete beam 3,

that in the sleeper bodies 3 in the upper region transversely of therail position are horizontal cylindrical openings, which were left openalready during concreting and recur at regular intervals and also allowthe subsequent installation of a point mechanism.

BRIEF DESCRIPTION OF THE DRAWING

An embodiment of the invention is illustrated in the drawings in which:

FIGS. 1-6 are cross sections showing the successive steps of making thetrack system of this invention;

FIG. 7 is a large-scale view of the left-hand portion of FIG. 6; and

FIG. 8 is a view like FIG. 5 showing further details of the invention.

SPECIFIC DESCRIPTION

FIG. 1 shows a cross section through the new type of reinforced concretebeam 3 in the form of a prefabricated part. It is possible to see thevarious fastening profiles 16, which are embedded in concrete mainly inbeam direction over the length of the beam and of which the fasteningprofile embedded in concrete at the upper edge transversely of the beamis used to fasten the rail and recurs in the rail fastening spacing. Itis moreover possible to see the passage prepared for the drainage pipes8.

FIG. 2 shows in cross section a matching pair of the reinforced concretebeams 3 at the start of prefabrication of a longitudinal sleeper frame2. The, in each case, bottom fastening profiles 16 in beam longitudinaldirection have already been used for the impervious connection of thefoil 5.

FIG. 3 shows in cross section a pair of reinforced concrete beams 3, thegauge of which has already been fixed by means of the bottom steelstructure 4. The connection between beam 3 and steel structure 4 iseffected likewise by means of the respective fastening profiles 16.

FIG. 4 shows a cross section through a fully preassembled longitudinalsleeper frame 2. By means of the fastening profiles 16, the transport-and concreting safety device 10 is connected non-positively to the pairof reinforced concrete beams 3 and the top and bottom longitudinal andtransverse reinforcements 9 are fixed to the steel structure 4. Thedrainage pipes 8 have likewise been preassembled.

FIG. 5 shows a cross section through a longitudinal sleeper frame 2assembled in situ. The sound deadening mat 6 is additionally situatedbetween the foil 5 of the longitudinal sleeper frame 2 and the frostprotection layer 1. The trough, which is formed by the pair ofreinforced concrete beams 3 and the frost protection layer 1 and sealedoff by the foil 5, is filled with casting concrete 7, which wasintroduced and compacted with a slight slope towards the inlets of thedrainage pipes 8. After setting of this concrete, the transport- andconcreting safety device may be removed and recycled.

FIG. 6 shows a cross section through the ready-to-operate “new type offixed track system for rail traffic”. After removal of the transport-and concreting safety device 10, the rails 14 with rail fastening andrail support 15 are non-positively connected by the upper fasteningprofiles 16 to the longitudinal sleeper frame 2. At the outside of eachof the reinforced concrete beams 3, gravel ballast 17 is introduced as aprotective and filtering layer.

FIG. 7 shows, for the sake of greater clarity, an enlarged detail fromFIG. 6.

FIG. 8 shows a cross section through the support region of thelongitudinal sleeper frame 2. It is possible to see the concretehigh-pressure injection piles 11, that have been introduced in pairsinto the grown soil 18, and the vertical steel girders 12 fixed thereinand the finely adjustable steel supports 13 situated thereon. Beforeintroduction of the casting concrete 7, the longitudinal sleeperframe(s) are connected non-positively and in a precisely positionedmanner by the inner fastening profiles 16 to the steel support 13.Incorporated in the support region is an additional pillar reinforcement19.

According to the invention, negative aspects of the fixed track, such ase.g. the extremely costly soil exchange, become redundant. Instead of,as before, having to completely exchange the existing soil at times to adepth of 3.0 m, an adequately dimensioned (max. 80 cm) frost protectionlayer 1 is sufficient as a protective and base layer on the grown soil18. This renders the system suitable also for existing soils that havevery poor and poor load-bearing capacity properties.

By virtue of extensive prefabrication of the longitudinal sleeper frame2 comprising the reinforced concrete beams 3, the steel structure 4 aswell as a transport- and concreting safety device in the form of steelstructure 10, a substantial amount of cost and time is saved and so railsections may be retrofitted or renovated occasionally without trafficinterruption, during the night or with minimal restrictions up to 400 min a shift are theoretically possible.

The reinforced concrete beams 3 are industrially prefabricated withmaximum dimensional accuracy and minimum quality variations.Furthermore, the two matching parallel beams 3 are assembled by means ofthe connecting and bracing steel structures 4, 10 to the required linearmeasure, which is also still transportable, and provided with a foil 5that is to be applied to the underside. In the installed state, thisfoil 5 together with a sound deadening mat 6 for acoustic isolation oftrack body and substructure forms the bottom termination relative to thefrost protection layer 1 and prevents an escape of casting concrete 7.

Simply by suitably varying the dimension of the steel structures 4, 10transversely of the rail position 14, any desired variation of the gaugeof the finished track may be achieved without modifying the reinforcedconcrete beams 3.

Prefabrication likewise includes the provision of drainage by means ofdrainage pipes 8, which are run through the beam 3 and by means of whichretained water situated between the beams is carried from there to theexterior of the overall structure.

Already at the preassembly stage, moreover, the top and bottomlongitudinal and transverse reinforcement 9 is inserted and fixed inposition by means of the above-mentioned steel structure 4.

Above the reinforcement 9 and the casting concrete 7 that is to beincorporated later, a further recyclable, adequately dimensioned steelstructure is installed as transport- and concreting safety device 10.

The actual static fastening is effected by means of concrete piles 11,which are inserted in pairs using high-pressure injection and in whichsteel girders 12 are introduced, or by means of conventionallarge-diameter bored piles made of reinforced concrete, onto which asteel support 13 is fitted transversely of the subsequent rail position14. After precise adjustment of this support 13 in height, longitudinaldirection and transverse direction, the preassembled longitudinalsleeper frame 2 is laid on, aligned and fastened. The static and dynamicforces that arise are diverted via the composite piles 11, 12 and thesteel support 13. This foundation work need be laid only ca. every 10running meters, with the result that high surveying and leveling outlayprevalent with old systems to a large extent no longer applies. Theseinjection piles 11, 12 may moreover be introduced with relatively lowprecision requirements in an existing section e.g. during the nightbreak, so that setting of the concrete may occur under operatingconditions. The exact alignment is effected, as described above, bymeans of the steel support 13.

The hollow space (concreting trough) formed by the preassembledreinforced concrete beam structure forminq the sleeper frame 2 is firstlined with additional reinforcement 19 in the support region and thenfilled with casting concrete 7, carefully compacted, leveled andprovided with an adequate slope for surface water to run in thedirection of the drainage pipes 8. For this purpose, high-early-strengthconcrete should be used. From a static viewpoint, this longitudinalfilling with concrete produces an infinitely long plate having excellentproperties with regard to the diversion of dynamic forces fromacceleration, deceleration and other dynamic forces arising frommovement of the rail traffic. Filling the space between sleepersmoreover allows optimum contact with the subsoil (frost protectionlayer) 1.

After hardening of the casting concrete 7, the transport- and concretingsafety device 10 is removed.

The rails 14 are then mounted, not as before on a track grating ofindividual sleepers or concrete-block and steel tie-bars disposed atright angles, but on the two parallel-running, statically adequatelydimensioned and e.g. prestressed reinforced concrete beams 3 of variablelength by means of the conventional connecting means 15. It is thereforepossible, here, fully to exhaust the maximum cut-up rail length of 360m. Here too, the rail inclination is produced, as usual, by means of astandard ribbed plate 15. All of these rail fastening points 15 arelater accessible at all times.

By virtue of fastening profiles 16 at the inside and outside of bothbeams 3 that have previously been simultaneously embedded in thereinforced concrete longitudinal sleepers 3 during the prefabricationphase, a subsequent fixed provision of noise protection measures orpoint constructions is easily possible. These are then just as easy toremove, shift to a different position or exchange.

A gravel layer 17 may be installed laterally of the finished trackbodies and between the track bodies of a multi-track section.

Thus, the direct advantages of the invention, namely a new type of fixedtrack system, lie above all in the lower construction costs, the highinstallation speed, the relative independence from the subsoil and thesubsequent variability of the track pattern.

1. A method of making a track system, the method comprising the stepsof: prefabricating a plurality of sleeper frames each including a pairof longitudinally extending rigid concrete beams held togethertransversely by a rigid steel structure; introducing pairs of concretepiles into grown soil with steel girders fixed in the piles; fixingtransverse steel supports to the girders of the piles; positioning andfastening the prefabricated sleeper frames on the steel supports;casting a longitudinally extending body of concrete between the beamsaround the steel structure and around upper ends of the girdersunderneath the steel structure; and after hardening of the castconcrete, mounting longitudinally extending rails atop the beams.
 2. Themethod defined in claim 1 wherein the sleeper frames are secured to thesupports via their rigid steel structures.
 3. The method defined inclaim 1, further comprising the step of: filling to each transverse sideof the frame with ballast after positioning the sleeper frames atop thepiles.
 4. The method defined in claim 1, further comprising the stepsbefore positioning the beams atop the piles of: forming the longitudinalbeams and providing each of them with fastening profiles; and securingthe rigid steel structure to the profiles to transversely fixedly spacethe beams and create the frames.
 5. The method defined in claim 4,further comprising the step after forming the beams but before 3securing the structure to the profiles of: securing underneath each pairof beams a respective flexible foil, the foil being stretched betweenthe beams by spreading the beams apart prior to securing the structureto the profiles.